Since the trivalent atoms, i.e. dopant having valency 3 i.e an element whose each atom has 3 valence electrons is called Trivalent impurity. For ex. Indium ,Gallium,Aluminium,Boron ,etc. These impurities are known as Acceptor impurities.As they accept electrons from the covalent bonds of Si, Ge.

We’re continuing in 8.2 with semiconductor doping. Impurities are added to intrinsic semiconductor materials to improve the electrical properties of the material. The process is referred to as doping. The resulting material is called an extrinsic semiconductor.

When a trivalent impurity (like Boron, Aluminum etc.) is added to an intrinsic or pure semiconductor (silicon or germanium), it is said to be a p-type semiconductor. A p-type semiconductor has more holes than electrons. This allows the current to flow along the material from hole to hole but only in one direction.

Trivalent impurity atoms have 3 valence electrons. The various examples of trivalent impurities include Boron (B), Gallium (G), Indium(In), Aluminium(Al). Boron is a substance consisting of atoms which all have the same number of protons.

The term n-type comes from the negative charge of the electron. In n-type semiconductors, electrons are the majority carriers and holes are the minority carriers. A common dopant for n-type silicon is phosphorus or arsenic.

When P-type and N-type come into contact, carriers, which are holes and free electrons, are attracted to each other, recombine at the junction of P-type and N-type, and disappear. Because there are no carriers near the junction, it is called a depletion layer, and it becomes the same state as an insulator.

Holes in a metal or semiconductor crystal lattice can move through the lattice as electrons can, and act similarly to positively-charged particles. They play an important role in the operation of semiconductor devices such as transistors, diodes and integrated circuits.

Holes and electrons are the two types of charge carriers responsible for current in semiconductor materials. A hole is the absence of an electron in a particular place in an atom. Although it is not a physical particle in the same sense as an electron, a hole can be passed from atom to atom in a semiconductor material.

The doping alters the band structure of the semiconductor so that there are “missing” electrons (holes) in the valence band. This allows other electrons to “move” from an atom to a nearby one without jumping into the conduction band: they fill a hole “near to them”, leaving a hole “behind them”.

2 Answers. In a semiconductor, there are contributions to the total electric current from both electrons in the conduction band and holes in the valence band. For N-type material, there are far more electrons in the conduction band than there are holes in the valence band.

A depletion region forms instantaneously across a p–n junction. In a N-side region near to the junction interface, free electrons in the conduction band are gone due to (1) the diffusion of electrons to the P-side and (2) recombination of electrons to holes that are diffused from the P-side.

Current that is caused by electron motion is called electron current and current that is caused by hole motion is called hole current. When the valence electron moves from valence band to the conduction band a vacancy is created in the valence band where electron left. Such vacancy is called hole.

The mobility is proportional to the carrier relaxation time and inversly proportionnal to the carrier effective mass. The electron mobilty is often greater than hole mobility because quite often, the electron effective mass is smaller than hole effective mass.

Current flow in a semiconductor arises from the motion of charge carriers in both the conduction and valence bands. As explained in chapter 4, the mobile charges in the conduction band are electrons and those in the valence band are holes.

When the diode is forward-biased, it can be used in LED lighting applications. It is used as rectifiers in many electric circuits and as a voltage-controlled oscillator in varactors….Applications of PN Junction Diode.

Diodes. Diodes allow current flow in one direction but not the other. A diode is called a diode because it has two distinct electrodes (i.e. terminals), called the anode and the cathode. A diode is electrically asymmetric because current can flow freely from the anode to the cathode, but not in the other direction.

The sudden increase in current in a zener diode is due to the rupture of many covalent bonds.

How reverse current suddenly increase at the breakdown voltage in case of zener diode? Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams. As the reverse bias voltage across the junction is increased, the electric field at the junction becomes significant.

Difference between Knee Voltage and Breakdown Voltage The forward voltage at which the flow of current during the PN Junction begins increasing quickly is known as knee voltage. It is the position within the forward bias of the curve wherever conduction begins to raise quickly of a PN-Junction Diode.

The maximum reverse bias voltage that can be applied to a p-n diode is limited by breakdown. Breakdown is characterized by the rapid increase of the current under reverse bias. The corresponding applied voltage is referred to as the breakdown voltage.